Alternatives in polymerization contraction stress management.

Polymerization contraction stress of dental composites is often associated with marginal and interfacial failures of bonded restorations. The magnitude of stress depends on composite composition (filler content and matrix composition) and its ability to flow before gelation, which is related to the cavity configuration and curing characteristics of the composite. This article reviews variations among studies regarding contraction-stress-testing methods and contraction stress values of current composites, and discusses the validity of contraction stress studies in relation to results from microleakage tests. The effects of lower curing rates and alternative curing routines on contraction stress values are also discussed, as well as the use of low-elastic-modulus liners. Moreover, studies with experimental dimethacrylate-based composites and recent developments in low-shrinkage monomers are described.